1. Field of the Invention
This invention relates generally to undervoltage detecting and tripping devices and it relates specifically to devices of this type using solid state circuitry.
2. State of the Prior Art
U.S. Pat. No. 3,557,040 by Richard H. Campbell, Jr. issued on May 4, 1971 and entitled "Solenoid Control Circuit" teaches an electronic circuit for actuating a solenoid load from an AC power source and a two step sequence wherein a high DC voltage is initially applied to pull in the solenoid armature after which the lower voltage maintains the armature in a hold condition. While this circuit requires two separate AC voltage levels for operation, it would be advantageous if a circuit could be devised utilizing only one level of sensing and energizing voltage. U.S. Pat. No. 3,582,716 by Richard O. Tralma issued June 1, 1971 and entitled "Apparatus For Providing Time Delay Upon Total Deenergization" teaches a solid state apparatus for providing an output at the end of a predetermined delay interval commencing with the total deenergization of the apparatus. It would be advantageous if a device could be provided which would provide an output at the beginning of a predetermined delay interval commencing with the total energization of an apparatus. U.S. Pat. 3,512,048 by K. D. Wallentowitiz et al issued May 12, 1970 and entitled "Electronic Timer Circuit" teaches the energization of a load after a timing cycle has been completed as was mentioned previously here would be advantageous to provide a device which would teach energization of a load drawing a timing cycle. Finally, U.S. Pat. No. 3,343,036 issued Sept. 19, 1967 to S. L. Steen and entitled "Static Undervoltage Circuit" primarily teaches a circuit which is utilized to turn off after a time delay. As was mentioned previously, it would be advantageous to teach the turning on of a load with the energization of a load with time delay where the energy supplied to the load could be reduced after the appropriate time delay.